WALLOPS ISLAND, Va. — A commercial spacecraft bound for the
International Space Station is cleared to launch from Virginia's
frigid Eastern Shore Wednesday (Jan. 8) in a milestone delivery
mission for its builder, Orbital Sciences Corp.

The unmanned Cygnus cargo ship is slated to blast off Wednesday
at 1:32 p.m. EST (1832 GMT) on the first Orbital
Sciences resupply mission under a $1.9 billion contract
between the company and NASA. The gleaming silver spacecraft will
launch atop an Antares rocket, also built by Orbital Sciences,
from a pad here at NASA's Wallops Flight Facility.

Orbital's Cygnus spacecraft is packed with 2,780 pounds (1,260
kilograms) of supplies for the six astronauts on the space
station. That haul includes a veritable cornucopia of science
experiments for the crew, including 33 tiny cubesat satellites to
be launched from the station and 23 experiments designed by
students on Earth.

The spacecraft is also carrying a space ant farm to study how
ants behave in weightlessness — an experiment to study the ants'
swarm intelligence that could help improve mathematical
procedures for solving complex problems, NASA officials said.

The Dulles, Va.-based Orbital Sciences hoped to launch the Cygnus
mission, called Orb-1, to the space station in mid-December, but
an unrelated cooling system malfunction on the orbiting lab
forced NASA to delay the flight while astronauts performed
emergency spacewalk repairs. Orbital later rescheduled the launch
for Jan. 7, then
delayed the mission due to the extreme freezing temperatures
blanketing much of the United States this week.

Orbital launch rules require temperatures of at least 20 degrees
Fahrenheit (minus 6 degrees Celsius) in order to fly. Over the
last few days, Orbital technicians have weathered sub-freezing
temperatures and biting wind-chill by working in shorter shifts
and taking shelter in a heated truck when needed.

"The main thing is keeping everybody warm and safe, with no
frostbite," Pinkston said.

Wednesday is forecast to be warmer, however, and officials say
there's a 95 percent chance that the weather will be good enough
for the Antares to get off the ground.

Orbital Sciences is one of two commercial spaceflight companies
tapped by NASA to fly unmanned cargo delivery mission to the
space station under billion-dollar contracts. The other company
is Hawthorne, Calif.-based SpaceX, which has launched two of 12
missions to the station using its Falcon 9 rockets and Dragon
space capsules.

Orbital's first
Antares rocket and Cygnus test flights launched in 2013, but
Wednesday's mission will mark the company's first of eight
official delivery missions under its $1.9 billion contract with
NASA.

Commercial spaceflight's big year

The Orb-1 mission comes on the heels of a Monday
SpaceX launch of a Falcon 9 rocket from Florida. That mission
lofted the commercial Thaicom 6 communications satellite into
orbit from Cape Canaveral Air Force Station — the first
commercial launch of 2014.

"This is going to be a big week for spaceflight in the U.S.,"
said Orbital executive vice president Frank Culbertson, a former
NASA astronaut, as he congratulated SpaceX's successful launch.
"I think you're going to see that the United States is going to
build up our launch rate."

NASA retired its space shuttle fleet in 2011 and now relies on
Orbital Sciences and SpaceX to launch delivery missions to the
space station. The U.S. agency is also reliant on cargo ships
launched by Russia, Japan and Europe to keep the station stocked,
and Russian Soyuz spacecraft to ferry astronauts to and from the
orbiting lab.

NASA plans to rely on U.S.-built commercial spacecraft to fly
American astronauts to the space station once they become
available.